binutils-gdb/gdb/c-valprint.c

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/* Support for printing C values for GDB, the GNU debugger.
Copyright (C) 1986-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "value.h"
#include "valprint.h"
#include "language.h"
#include "c-lang.h"
#include "cp-abi.h"
#include "target.h"
#include "objfiles.h"
/* A helper for c_textual_element_type. This checks the name of the
typedef. This is bogus but it isn't apparent that the compiler
provides us the help we may need. */
static int
textual_name (const char *name)
{
return (!strcmp (name, "wchar_t")
|| !strcmp (name, "char16_t")
|| !strcmp (name, "char32_t"));
}
/* Apply a heuristic to decide whether an array of TYPE or a pointer
to TYPE should be printed as a textual string. Return non-zero if
it should, or zero if it should be treated as an array of integers
or pointer to integers. FORMAT is the current format letter, or 0
if none.
We guess that "char" is a character. Explicitly signed and
unsigned character types are also characters. Integer data from
vector types is not. The user can override this by using the /s
format letter. */
int
c_textual_element_type (struct type *type, char format)
{
struct type *true_type, *iter_type;
if (format != 0 && format != 's')
return 0;
/* We also rely on this for its side effect of setting up all the
typedef pointers. */
true_type = check_typedef (type);
/* TYPE_CODE_CHAR is always textual. */
if (TYPE_CODE (true_type) == TYPE_CODE_CHAR)
return 1;
/* Any other character-like types must be integral. */
if (TYPE_CODE (true_type) != TYPE_CODE_INT)
return 0;
/* We peel typedefs one by one, looking for a match. */
iter_type = type;
while (iter_type)
{
/* Check the name of the type. */
if (TYPE_NAME (iter_type) && textual_name (TYPE_NAME (iter_type)))
return 1;
if (TYPE_CODE (iter_type) != TYPE_CODE_TYPEDEF)
break;
/* Peel a single typedef. If the typedef doesn't have a target
type, we use check_typedef and hope the result is ok -- it
might be for C++, where wchar_t is a built-in type. */
if (TYPE_TARGET_TYPE (iter_type))
iter_type = TYPE_TARGET_TYPE (iter_type);
else
iter_type = check_typedef (iter_type);
}
if (format == 's')
{
/* Print this as a string if we can manage it. For now, no wide
character support. */
if (TYPE_CODE (true_type) == TYPE_CODE_INT
&& TYPE_LENGTH (true_type) == 1)
return 1;
}
else
{
/* If a one-byte TYPE_CODE_INT is missing the not-a-character
flag, then we treat it as text; otherwise, we assume it's
being used as data. */
if (TYPE_CODE (true_type) == TYPE_CODE_INT
&& TYPE_LENGTH (true_type) == 1
&& !TYPE_NOTTEXT (true_type))
return 1;
}
return 0;
}
/* Decorations for C. */
static const struct generic_val_print_decorations c_decorations =
{
"",
" + ",
" * I",
"true",
"false",
"void"
};
/* See val_print for a description of the various parameters of this
function; they are identical. */
void
c_val_print (struct type *type, const gdb_byte *valaddr,
int embedded_offset, CORE_ADDR address,
struct ui_file *stream, int recurse,
const struct value *original_value,
const struct value_print_options *options)
{
struct gdbarch *gdbarch = get_type_arch (type);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
unsigned int i = 0; /* Number of characters printed. */
unsigned len;
struct type *elttype, *unresolved_elttype;
struct type *unresolved_type = type;
unsigned eltlen;
CORE_ADDR addr;
CHECK_TYPEDEF (type);
switch (TYPE_CODE (type))
{
case TYPE_CODE_ARRAY:
unresolved_elttype = TYPE_TARGET_TYPE (type);
elttype = check_typedef (unresolved_elttype);
if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (unresolved_elttype) > 0)
{
LONGEST low_bound, high_bound;
if (!get_array_bounds (type, &low_bound, &high_bound))
error (_("Could not determine the array high bound"));
eltlen = TYPE_LENGTH (elttype);
len = high_bound - low_bound + 1;
if (options->prettyformat_arrays)
{
print_spaces_filtered (2 + 2 * recurse, stream);
}
/* Print arrays of textual chars with a string syntax, as
long as the entire array is valid. */
if (c_textual_element_type (unresolved_elttype,
options->format)
&& value_bytes_available (original_value, embedded_offset,
TYPE_LENGTH (type))
&& !value_bits_any_optimized_out (original_value,
TARGET_CHAR_BIT * embedded_offset,
TARGET_CHAR_BIT * TYPE_LENGTH (type)))
{
int force_ellipses = 0;
/* If requested, look for the first null char and only
print elements up to it. */
if (options->stop_print_at_null)
{
unsigned int temp_len;
for (temp_len = 0;
(temp_len < len
&& temp_len < options->print_max
&& extract_unsigned_integer (valaddr + embedded_offset
+ temp_len * eltlen,
eltlen, byte_order) != 0);
++temp_len)
;
/* Force LA_PRINT_STRING to print ellipses if
we've printed the maximum characters and
the next character is not \000. */
if (temp_len == options->print_max && temp_len < len)
{
ULONGEST val
= extract_unsigned_integer (valaddr + embedded_offset
+ temp_len * eltlen,
eltlen, byte_order);
if (val != 0)
force_ellipses = 1;
}
len = temp_len;
}
LA_PRINT_STRING (stream, unresolved_elttype,
valaddr + embedded_offset, len,
NULL, force_ellipses, options);
i = len;
}
else
{
fprintf_filtered (stream, "{");
/* If this is a virtual function table, print the 0th
entry specially, and the rest of the members
normally. */
if (cp_is_vtbl_ptr_type (elttype))
{
i = 1;
fprintf_filtered (stream, _("%d vtable entries"),
len - 1);
}
else
{
i = 0;
}
val_print_array_elements (type, valaddr, embedded_offset,
address, stream,
recurse, original_value, options, i);
fprintf_filtered (stream, "}");
}
break;
}
/* Array of unspecified length: treat like pointer to first
elt. */
addr = address + embedded_offset;
goto print_unpacked_pointer;
case TYPE_CODE_METHODPTR:
cplus_print_method_ptr (valaddr + embedded_offset, type, stream);
break;
case TYPE_CODE_PTR:
if (options->format && options->format != 's')
{
val_print_scalar_formatted (type, valaddr, embedded_offset,
original_value, options, 0, stream);
break;
}
if (options->vtblprint && cp_is_vtbl_ptr_type (type))
{
/* Print the unmangled name if desired. */
/* Print vtable entry - we only get here if we ARE using
-fvtable_thunks. (Otherwise, look under
TYPE_CODE_STRUCT.) */
CORE_ADDR addr
= extract_typed_address (valaddr + embedded_offset, type);
print_function_pointer_address (options, gdbarch, addr, stream);
break;
}
unresolved_elttype = TYPE_TARGET_TYPE (type);
elttype = check_typedef (unresolved_elttype);
{
int want_space;
addr = unpack_pointer (type, valaddr + embedded_offset);
print_unpacked_pointer:
want_space = 0;
if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
{
/* Try to print what function it points to. */
print_function_pointer_address (options, gdbarch, addr, stream);
return;
}
if (options->symbol_print)
want_space = print_address_demangle (options, gdbarch, addr,
stream, demangle);
else if (options->addressprint)
{
fputs_filtered (paddress (gdbarch, addr), stream);
want_space = 1;
}
/* For a pointer to a textual type, also print the string
pointed to, unless pointer is null. */
if (c_textual_element_type (unresolved_elttype,
options->format)
&& addr != 0)
{
if (want_space)
fputs_filtered (" ", stream);
i = val_print_string (unresolved_elttype, NULL,
addr, -1,
stream, options);
}
else if (cp_is_vtbl_member (type))
{
/* Print vtbl's nicely. */
CORE_ADDR vt_address = unpack_pointer (type,
valaddr
+ embedded_offset);
struct bound_minimal_symbol msymbol =
lookup_minimal_symbol_by_pc (vt_address);
/* If 'symbol_print' is set, we did the work above. */
if (!options->symbol_print
&& (msymbol.minsym != NULL)
&& (vt_address == BMSYMBOL_VALUE_ADDRESS (msymbol)))
{
if (want_space)
fputs_filtered (" ", stream);
fputs_filtered (" <", stream);
fputs_filtered (MSYMBOL_PRINT_NAME (msymbol.minsym), stream);
fputs_filtered (">", stream);
want_space = 1;
}
if (vt_address && options->vtblprint)
{
struct value *vt_val;
struct symbol *wsym = (struct symbol *) NULL;
struct type *wtype;
struct block *block = (struct block *) NULL;
struct field_of_this_result is_this_fld;
if (want_space)
fputs_filtered (" ", stream);
if (msymbol.minsym != NULL)
wsym = lookup_symbol (MSYMBOL_LINKAGE_NAME (msymbol.minsym),
block, VAR_DOMAIN,
&is_this_fld);
if (wsym)
{
wtype = SYMBOL_TYPE (wsym);
}
else
{
wtype = unresolved_elttype;
}
vt_val = value_at (wtype, vt_address);
common_val_print (vt_val, stream, recurse + 1,
options, current_language);
if (options->prettyformat)
{
fprintf_filtered (stream, "\n");
print_spaces_filtered (2 + 2 * recurse, stream);
}
}
}
return;
}
break;
case TYPE_CODE_UNION:
if (recurse && !options->unionprint)
{
fprintf_filtered (stream, "{...}");
break;
}
/* Fall through. */
case TYPE_CODE_STRUCT:
/*FIXME: Abstract this away. */
if (options->vtblprint && cp_is_vtbl_ptr_type (type))
{
/* Print the unmangled name if desired. */
/* Print vtable entry - we only get here if NOT using
-fvtable_thunks. (Otherwise, look under
TYPE_CODE_PTR.) */
int offset = (embedded_offset
+ TYPE_FIELD_BITPOS (type,
VTBL_FNADDR_OFFSET) / 8);
struct type *field_type = TYPE_FIELD_TYPE (type,
VTBL_FNADDR_OFFSET);
CORE_ADDR addr
= extract_typed_address (valaddr + offset, field_type);
print_function_pointer_address (options, gdbarch, addr, stream);
}
else
cp_print_value_fields_rtti (type, valaddr,
embedded_offset, address,
stream, recurse,
original_value, options,
NULL, 0);
break;
case TYPE_CODE_INT:
if (options->format || options->output_format)
{
struct value_print_options opts = *options;
opts.format = (options->format ? options->format
: options->output_format);
val_print_scalar_formatted (type, valaddr, embedded_offset,
original_value, &opts, 0, stream);
}
else
{
val_print_type_code_int (type, valaddr + embedded_offset,
stream);
/* C and C++ has no single byte int type, char is used
instead. Since we don't know whether the value is really
intended to be used as an integer or a character, print
the character equivalent as well. */
if (c_textual_element_type (unresolved_type, options->format))
{
fputs_filtered (" ", stream);
LA_PRINT_CHAR (unpack_long (type, valaddr + embedded_offset),
unresolved_type, stream);
}
}
break;
case TYPE_CODE_MEMBERPTR:
if (!options->format)
{
cp_print_class_member (valaddr + embedded_offset, type, stream, "&");
break;
}
/* FALLTHROUGH */
case TYPE_CODE_REF:
case TYPE_CODE_ENUM:
case TYPE_CODE_FLAGS:
case TYPE_CODE_FUNC:
case TYPE_CODE_METHOD:
case TYPE_CODE_BOOL:
case TYPE_CODE_RANGE:
case TYPE_CODE_FLT:
case TYPE_CODE_DECFLOAT:
case TYPE_CODE_VOID:
case TYPE_CODE_ERROR:
case TYPE_CODE_UNDEF:
case TYPE_CODE_COMPLEX:
case TYPE_CODE_CHAR:
default:
generic_val_print (type, valaddr, embedded_offset, address,
stream, recurse, original_value, options,
&c_decorations);
break;
}
gdb_flush (stream);
}
void
c_value_print (struct value *val, struct ui_file *stream,
const struct value_print_options *options)
{
struct type *type, *real_type, *val_type;
int full, top, using_enc;
struct value_print_options opts = *options;
opts.deref_ref = 1;
/* If it is a pointer, indicate what it points to.
Print type also if it is a reference.
C++: if it is a member pointer, we will take care
of that when we print it. */
/* Preserve the original type before stripping typedefs. We prefer
to pass down the original type when possible, but for local
checks it is better to look past the typedefs. */
val_type = value_type (val);
type = check_typedef (val_type);
if (TYPE_CODE (type) == TYPE_CODE_PTR
|| TYPE_CODE (type) == TYPE_CODE_REF)
{
/* Hack: remove (char *) for char strings. Their
type is indicated by the quoted string anyway.
(Don't use c_textual_element_type here; quoted strings
are always exactly (char *), (wchar_t *), or the like. */
if (TYPE_CODE (val_type) == TYPE_CODE_PTR
&& TYPE_NAME (val_type) == NULL
&& TYPE_NAME (TYPE_TARGET_TYPE (val_type)) != NULL
&& (strcmp (TYPE_NAME (TYPE_TARGET_TYPE (val_type)),
"char") == 0
|| textual_name (TYPE_NAME (TYPE_TARGET_TYPE (val_type)))))
{
/* Print nothing. */
}
else if (options->objectprint
&& (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_STRUCT))
{
int is_ref = TYPE_CODE (type) == TYPE_CODE_REF;
if (is_ref)
val = value_addr (val);
/* Pointer to class, check real type of object. */
fprintf_filtered (stream, "(");
if (value_entirely_available (val))
{
real_type = value_rtti_indirect_type (val, &full, &top,
&using_enc);
if (real_type)
{
/* RTTI entry found. */
type = real_type;
/* Need to adjust pointer value. */
val = value_from_pointer (real_type,
value_as_address (val) - top);
if (is_ref)
{
val = value_ref (value_ind (val));
type = value_type (val);
}
/* Note: When we look up RTTI entries, we don't get
any information on const or volatile
attributes. */
}
}
type_print (type, "", stream, -1);
fprintf_filtered (stream, ") ");
val_type = type;
}
else
{
/* normal case */
fprintf_filtered (stream, "(");
type_print (value_type (val), "", stream, -1);
fprintf_filtered (stream, ") ");
}
}
if (!value_initialized (val))
fprintf_filtered (stream, " [uninitialized] ");
if (options->objectprint && (TYPE_CODE (type) == TYPE_CODE_STRUCT))
{
/* Attempt to determine real type of object. */
real_type = value_rtti_type (val, &full, &top, &using_enc);
if (real_type)
{
/* We have RTTI information, so use it. */
val = value_full_object (val, real_type,
full, top, using_enc);
fprintf_filtered (stream, "(%s%s) ",
TYPE_NAME (real_type),
full ? "" : _(" [incomplete object]"));
/* Print out object: enclosing type is same as real_type if
full. */
val_print (value_enclosing_type (val),
value_contents_for_printing (val), 0,
value_address (val), stream, 0,
val, &opts, current_language);
return;
/* Note: When we look up RTTI entries, we don't get any
information on const or volatile attributes. */
}
else if (type != check_typedef (value_enclosing_type (val)))
{
/* No RTTI information, so let's do our best. */
fprintf_filtered (stream, "(%s ?) ",
TYPE_NAME (value_enclosing_type (val)));
val_print (value_enclosing_type (val),
value_contents_for_printing (val), 0,
value_address (val), stream, 0,
val, &opts, current_language);
return;
}
/* Otherwise, we end up at the return outside this "if". */
}
val_print (val_type, value_contents_for_printing (val),
value_embedded_offset (val),
value_address (val),
stream, 0,
val, &opts, current_language);
}